1. How do I sync the Galaxy S3 with my Mac?
2. How do I sync it with iPhoto?

1. What do you mean sync it with you Mac? What do you want to sync exactly?

2. I'm not an expert on Android but I think you'll have to drag and drop. I don't think you'll be able to do a sync so that it updates automatically whenever you plug in your phone. I could be wrong though.

This can take 10 minutes or more to install. Be patient. It has to install Samsung usb drivers, plus the program itself. Once done connect S3 with the UsB cable that came with the phone and the rest will be self explainatory.

Option 2:
Download Android File Transfer app on your computer. Follow steps to transfer files in the program. This is a drag and drop program, not a sync type program.

Option 3:
Go to Google Play store and download an app called isyncr. Follow the directions.

This can take 10 minutes or more to install. Be patient. It has to install Samsung usb drivers, plus the program itself. Once done connect S3 with the UsB cable that came with the phone and the rest will be self explainatory.

Option 2:
Download Android File Transfer app on your computer. Follow steps to transfer files in the program. This is a drag and drop program, not a sync type program.

Option 3:
Go to Google Play store and download an app called isyncr. Follow the directions.

under USB PC connection, choose the camera option instead of the media device option, and then the phone will show up as a device in iPhoto. Then you can import, etc, although it may not automatically sync